I believe the CCT on my rear cylinder is going. I had the same issue on my 750 and bought the manual ones and they helped a great deal. I don't see any manual ones for the 1600 classic and its only my rear cylinder that has the knock. It is quite evident at the CCT itself, esp using a screwdriver stethoscope. Should I just replace it with a new one and how difficult a procedure is it. The vn750 was a snap, hopefully this will be something I can do. It's a deeper, harder knock sound than the 750 had so I believe the CCT is the culprit as it is worse right at it and not as loud in other areas.

I took her to a local independent cycle shop and the main guy said that it sounds quieter than most and I should just ride. My main issue is the knock is on the rear and not the front. It seems like its the CCT but what else could it be

I was worried to death about this. Its a piece of cake. Get the extensioners from chucksterscustoms .com $35 anticipating the next question & put them on. Be carefull during removal OR just go ahead & get new gaskets too. I was able to get mine OFF with out damage. Go to Gadgets page for step by step instructions OR follow this link, their BOTH good info.
Utah Motorcyclist: How to Install Cam Chain Tensioner Extenders on a Kawasaki Vulcan Nomad

It is quite common for the chain to have that loose slapping sound in between the take up points of the tensioner. At times they can sound bad for weeks on end then one day it is quiet till the chain wears a bit more etc. Don't panic yet ! If you install the extenders too soon you can damage the chain runner seriously enough to create a catastrofic situation. The tensioners must be near bottom of stroke before needing them.
If your tensioners are at full extension, then you will be able to use the extenders, BUTT be aware that when the chains wear and get longer, the cam's are being retarded by an equal amount, and the only true fix is to put on new chains, which admittedly is an ordeal requiring top end and side covers removal.
Retarded cams are noticeable and a worn chain can put it back by approx 3 deg. If you check it out you will find that the specs for cams and timing are usually spec'd out to a few Minuit's of a degree !